Java-Array application

I feel that sometimes Java is really awesome !!!

I think I can use Java...

I will continue to update this article. I think that if you want to use Java in ACM, you must make good use of arrays, so it is necessary to learn arrays well,

Step 1: I learned how to dynamically generate arrays and sort them more important,

Code:

Package com; import Java. util. arrays; import Java. util. dependencies; // import Java. util. arrays; public class demobinarysearch {public static void main (string [] ARGs) {custom input = new role (system. in); int N; while (input. hasnext () {n = input. nextint (); int [] A = new int [N]; // you have to say this is really amazing. You can also store variables when applying for memory .... for (INT I = 0; I <n; I ++) {A [I] = input. nextint ();} // arrays. sort (A, 0,. length); // The arrays of the N * log (n) algorithm. sort (a); // these two sorting methods are good. The first one is to sort as many elements as possible, in this way, you have to dynamically generate the number you need. // the second one is like the above one, indicating the start position and the last position. for (INT I = 0; I <n; I ++) {system. out. print (A [I]); system. out. print ("");} system. out. println ();}}}

Another useful binarysearch () ---- Binary Search

Package com; import Java. util. arrays; import Java. util. dependencies; // import Java. util. arrays; public class demobinarysearch {public static void main (string [] ARGs) {custom input = new role (system. in); int N; while (input. hasnext () {n = input. nextint (); int [] A = new int [N]; // you have to say this is really amazing. You can also store variables when applying for memory .... for (INT I = 0; I <n; I ++) {A [I] = input. nextint ();} // arrays. sort (A, 0,. length); // The arrays of the N * log (n) algorithm. sort (a); // these two sorting methods are good. The first one is to sort as many elements as possible, in this way, you have to dynamically generate the number you need. // the second one is like the above one, indicating the start position and the last position. for (INT I = 0; I <n; I ++) {system. out. print (A [I]); system. out. print ("");} system. out. println (); // int idx = arrays. binarysearch (A, 0,. length, 5); // Of course, the prerequisite for this binary is that the order has been sorted, int idx = arrays. binarysearch (A, 5); // binary search, this is also good. I said that Java has written all the things, so I am embarrassed to do so, we don't need to write anything. system. out. println ("The idx =" + (idx + 1 ));}}}

The following describes the fill and copy functions:

Package com; import Java. util. arrays; import Java. util. optional; public class demoarrays {public static int N; public static void print (INT [] A) {for (INT I = 0; I <. length; I ++) {system. out. print (A [I] + "");} n ++; system. out. println ();} public static void main (string [] ARGs) {int [] B; int [] C; input = new partition (system. in); While (input. hasnext () {n = input. nextint (); int [] A = new int [N]; arrays. Fill (A, 1); // The fill method is to directly fill all the content of the array into the same content B = arrays. copyof (A, 20); // copy the content of the array to array c = arrays. copyofrange (A, 0, 10); // copy the content 0-10 from array A to C; print (); // if you do not want to create an object to directly use the method in the class, you have to apply for a static method, and the static method can only use static variables. print (B); print (c); system. out. println (n); // here n is the N after execution of N ++. so we should know that static methods can only reference static constants, which is equivalent to global variables in C ++ !!! For (INT I = 0; I <n; I ++) {A [I] = input. nextint ();}}}}